我收到错误： class Document < ActiveRecord::Base
belongs_to :user
end
class User < ActiveRecord::Base
belongs_to :company
has_many :documents
end
class Company < ActiveRecord::Base
has_many :users
end
=== Query
selected_company: Company.first
documents_in_selected_company = Document.joins(:User).joins(:User => :Company).where(:company_id => selected_company[:id)
该错误必须在以下行中：
gurobipy.GurobiError: Invalid argument to LinExpr multiplication m.setObjective(quicksum(sum(s[d, r] *x[d, r] for r in piecewise)
* h[d] * Z * VarDemand[d] for d in demandStage)
+ quicksum(sum(s[j, r] * x[j, r] for r in piecewise)
*h[j] * Z * Var[j] for j in intermediateStage),
GRB.MINIMIZE)
是变量，其余的都是使用excel文件中的导入值的dicts。
我已经盯着这个很长一段时间了，但我看不出这个错误。